During the course of operation, internal combustion engines generate significant amounts of heat, which may be used to heat the interior (e.g., cabin) of a motor vehicle upon passenger request. Typically, cabin heating is accomplished with a device which extracts thermal energy from waste heat generated by the engine or from heat in a coolant, which may circulate through, and extract thermal energy from, the engine. However, as the operating efficiency of the engine increases, waste heat in the coolant may be insufficient for cabin heating. Various approaches may be taken in response to generate additional heat. Other strategies may used to generate heat for other purposes. In diesel engines having a diesel particulate filter (DPF), for example, the exhaust temperature may be raised to remove particulates trapped in the DPF to thereby regenerate the filter. One approach may involve altering the fuel injection strategy (e.g., retarding fuel injection) and supplying additional fuel to increase the exhaust temperature.
German Pat. No. 102006043086A1 discloses a system for generating a reducing agent in an exhaust gas system of a motor vehicle and a method for operating such a system, wherein a heating element generating the heat necessary for operation of the system selectively conducts heat to at least one device outside the system, for example an interior heater of a motor vehicle cabin.
German Pat. No. 60210528T2 discloses amongst others a diesel particle filter unit and a control method for its regeneration in which the exhaust gas temperature is raised during the regeneration process by delaying fuel injection.
European Pat. No. 1882829A1 discloses amongst others a method for controlling an exhaust gas cleaning system in which a device is used to raise the temperature of the exhaust gas by means of auxiliary injection at a time following normal combustion.
European Pat. No. 1517029A1 discloses a device and a method for regeneration of a DPF in which the exhaust gas temperature is raised by delaying fuel injection or by supplementary fuel injection, and wherein the increase in exhaust gas temperature is terminated on the basis of calculation of an effective regeneration time.
The inventors herein have recognized several issues with such approaches. In some cases, generation of adequate heat for filter regeneration and/or cabin heating requires the inclusion of an additional device, increasing vehicle cost, weight, and complexity. In other cases, generation of heat is carried out solely for the purpose of filter regeneration and is accomplished by adjusting the fuel injection strategy, which may have adverse effects including increased emissions, fuel consumption, and reduced efficiency.
The above issues may be at least partially addressed by a method for controlling regeneration of a particulate filter. In one example, a first phase of a filter regeneration event is initiated for a filter in an internal combustion engine based on one or more parameters. Heat produced by the engine is then supplied to a heater core during the first phase. The first phase is then extended if heating is requested. The engine may be operated at reduced efficiency during the filter regeneration event, including during the first phase. In some embodiments, the method may further include injecting an additional amount of fuel during a second phase of the filter regeneration event after the first phase ends to cause soot combustion in the filter. In one example, the first phase does not include injection of fuel into the exhaust.
In this way, sufficient supply of heat to a passenger compartment or vehicle cabin may be ensured by utilizing heat generated from a filter regeneration event. Additional supply of heat may also be provided by extending the filter regeneration event. Such an approach may be advantageous for diesel engines, for example, which may have difficulty supplying adequate heat to passengers.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.